package com.cctc.security.support;

import java.util.Collection;
import java.util.Iterator;

import org.springframework.security.access.AccessDecisionManager;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.access.ConfigAttribute;
import org.springframework.security.access.SecurityConfig;
import org.springframework.security.authentication.InsufficientAuthenticationException;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.stereotype.Component;

//访问决策器，决定某个用户具有的角色，是否有足够的权限去访问某个资源   
@Component("myAccessDecisionManager")
public class MyAccessDecisionManager implements AccessDecisionManager {

	@Override
	public void decide(Authentication authentication, Object object, Collection<ConfigAttribute> configAttributes)
			throws AccessDeniedException, InsufficientAuthenticationException {

		if (configAttributes == null) {
			return;
		}
		Iterator<ConfigAttribute> ite = configAttributes.iterator();

		while (ite.hasNext()) {
			ConfigAttribute ca = ite.next();
			String needRole = ((SecurityConfig) ca).getAttribute();
			//ga 为用户所被赋予的权限。 needRole 为访问相应的资源应该具有的权限。
			for (GrantedAuthority ga : authentication.getAuthorities()) {
				if (needRole.trim().equals(ga.getAuthority().trim())) {
					return;
				}
			}
		}
		throw new AccessDeniedException("");
	}

	@Override
	public boolean supports(ConfigAttribute configAttribute) {
		return true;
	}

	@Override
	public boolean supports(Class<?> arg0) {
		return true;
	}

}
